The present invention relates in general to systems and methods for reading utility meters and more particularly to systems and methods for remote reading of multi-digit displays on utility meters.
Multi-digit displays are common on the meters used by utility companies to record the consumption of gas, heat, electricity or water. Such records and displays are used by the utility company for billing purposes and by the customers as an indication of consumption.
A number of Automatic Meter Reading (AMR) systems have been devised, including S0 counting interface systems, optical character recognition (OCR) systems and non-visible coding systems. The S0 counting interface, which is the most common system, includes a small magnet mounted on the fastest turning wheel (the Least Significant Digit, LSD). As the magnet passes a fixed reference point a count is incremented. The count is typically stored in non volatile memory. In an optical character recognition system, an electronic apparatus is typically placed over the current mechanical display. The apparatus uses optical character recognition techniques to recognize the numbers on the display. Such a system is usually carried by a human meter reader and therefore addresses some accuracy issues but may not be cost effective. In a non-visible coding system, a machine readable code is marked on the wheels in a position not readily visible to a human reader, or such a code is marked on a duplicate set of wheels arranged to replicate the count of the primary wheels.
These above known solutions each have one or more disadvantages that limit their widespread use on the market. For example, one disadvantage is that a permanent electrical supply may be required which can pose a potential risk for fire or explosions in a meter, especially for gas meters. Another disadvantage is that a failure, accidental, intentional or malicious, to the power supply to the meter can cause failure of the count mechanism and loss of accuracy and revenue. In addition, the displayed value is assumed to be the same as the electronic value but this may not be the case which may lead to customer dissatisfaction.
Accordingly, it is desirable to provide remote meter reading systems. Such systems should be cost effective and have low power consumption requirements. Additionally, such systems should not be larger than the standard meters for retrofit.
The present invention provides low cost systems and methods for reading of multi-digit mechanical displays, such as the displays used in meters supplied by utility companies to record and display the individual customers"" consumption of gas, electricity or water. The system of the present invention uses an optical sensor to detect the value of the display by sensing the width of a shadow cast by a cam profile implemented onto the axis of existing mechanical display wheels. The arrangement allows for the remote reading via a modem on a telephone line, or via a radio link transmitted over a mobile network, or other such connections. The system is further arranged to have low power consumption and is preferably powered entirely from a telephone connection.
Considerable expertise and experience has been built into the design of such meters in terms of safety, accuracy, power supply independence and customer acceptance. The present invention therefore allows for the remote reading of mechanical displays such as are found in these established meters without the risk of compromising the current acceptability of such meters.
Remote reading of utility meters offers a number of benefits, including, for example:
Customers only pay for actual usage and not on estimated usage;
Customers can more easily exercise their right of choice between utility companies;
Customers can feel they have more immediate control over consumption and spending;
Traditional methods of manual meter reading can be time consuming, error prone and costly, especially where multiple meters are installed; and
High energy prices and energy related taxes increases the potential for fraud and remote reading allows for higher levels of monitoring to determine abnormal consumption patterns.
The present invention provides techniques for directly reading the position of each of the discs that make up the display by optically determining the width of a shadow cast by a cam profile attached to each wheel. The techniques of the present invention do not affect the existing display system or affect the accuracy and appearance of the current system.
In one embodiment of the invention the discs are read in parallel. In a second embodiment, the discs are read sequentially to save power. In another embodiment, the entire reading system is powered entirely from a modem connected to the telephone line and is inherently suitable for meters associated with gas systems and other such potentially combustible systems. In yet another embodiment, only one photosensor is used to read the position of the discs thereby additionally saving both cost and power.
According to an aspect of the present invention, a meter reading system is provided for determining the rotational position of one or more rotating display discs. The system typically includes a cam associated with each disc, wherein each cam rotates with the associated disc, a light source that illuminates each cam such as to project a shadow for each cam, and a light detecting element that detects the shadow of each cam and provides a signal representing parameters of each shadow. The system also typically includes a processor that determines the rotational position of each disc based on the respective shadow parameters provided by the light detecting element.
According to another aspect of the present invention, a method is provided for reading a meter having one or more rotating display discs. The method typically includes providing a cam associated with each disc, wherein each cam rotates with the associated disc, illuminating each cam so as to project a shadow on a light detecting element, and determining rotational position information for each disc based on the associated cam shadow detected by the light detecting element.
According to a further aspect of the present invention, a system is provided for remote reading of a display wherein the display is created by the alignment of one or more discs mounted and rotated around a common axis. The system typically includes a projection mounted on or part of each of said discs substantially at right angles to the plane of rotation of the discs, a separate light emitting means and lens means associated with each disc, a photo-detection means associated with each disc, wherein the profile of said projection being such that when illuminated by said light emitting means the width and position of the shadow cast by said projection onto said photo-detection means allows for the determination of the rotational position of the disc. The system also typically includes a control means to control the light emitting means and read the photo-detection means such as to determine the position of each disc, and communication means to transmit the determined positions of the discs to a remote reader.
According to yet a further aspect of the present invention, a system is provided for remote reading of a display wherein the display is created by the alignment of one or more discs mounted and rotated around a common axis. The system typically includes a projection mounted on or part of each of said discs substantially at right angles to the plane of rotation of the discs, a separate light emitting means and lens means associated with each disc, and an optical arrangement arranged to reflect each of the shadows cast by the projections onto a single photo-detection means, the profile of said projection being such that when illuminated by said light emitting means the width and position of the shadow cast by said projection onto said photo-detection means allows for the determination of the rotational position of the disc. The system also typically includes control means to control the light emitting means and read the photo-detection means such as to determine the position of each disc, and communication means to transmit the determined positions of the discs to a remote reader.
Reference to the remaining portions of the specification, including the drawings and claims, will realize other features and advantages of the present invention. Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with respect to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements.